As an inner-slide sunroof device, there is known a sunroof device, in which a rear cam boss is provided on a rear part of a panel bracket attached to each side edge of a sunroof panel, a channel-shaped guide rail defining a rear boss guide groove that opens laterally to guide the rear cam boss is provided on a roof, and a rear guide member forming a cam groove is attached to a part of the guide rail at which an upper wall thereof is partly removed (Patent Document 1). In this sunroof device, the rear cam boss slidably engaging the rear boss guide groove is guided by the rear guide member such that transition between a tilting operation and a horizontal movement operation of the sunroof panel is performed smoothly.